Curve guide on linked object
Particle systems can't be linked into a scene dynamically. So you can't change the shape of the hair from what it is in the original file. You'll have to append the emitter as a local object.

An alternative, for braided hair that could work well, is to model the braids as a mesh object with either particles wrapped around it or a texture. Then use the curve guides+hooks+armature proxy system to animate that.